Surface coating method for hydrophobic and superhydrophobic treatment in atmospheric pressure plasma

• US 20100221452A1
• Filed: 07/07/2006
• Published: 09/02/2010
• Est. Priority Date: 07/09/2005
• Status: Active Grant

• Current Assignee: Bang-Kwon Kang
• Original Assignee: Bang-Kwon Kang
• Inventors: Kang, Bang-Kwon
• Granted Patent: US 8,771,806 B2
• Time in Patent Office: Days
• US Class Current: 427/577
• CPC Class Codes: B05D 1/62 Plasma-deposition of organic layers plasma deposition in general C23C14/00, C23C16/00
• CPC Class Codes: B05D 2201/04 Laminate
• CPC Class Codes: B05D 2202/00 Metallic substrate
• CPC Class Codes: B05D 2203/35 Glass
• CPC Class Codes: B05D 5/083 involving the use of fluoropolymers
• CPC Class Codes: C23C 16/22 characterised by the deposition of inorganic material, other than metallic material
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34

Abstract

The present invention relates to a method of coating fluorocarbon or hydrocarbon on the surface of a workpiece using atmospheric pressure plasma. More particularly, the present invention relates to a method of coating hydrocarbon or fluorocarbon on the surface of a workpiece using plasma generated under atmospheric pressure such that the workpiece can have a hydrophobic or super-hydrophobic surface.

The method of coating a surface of a workpiece with fluorocarbon to be hydrophobic or super-hydrophobic according to the present invention comprises the steps of generating first atmospheric pressure glow plasma by supplying a reaction gas into a discharge space formed between a first electrode and a second electrode, the reaction gas containing hydrogen gas, fluorocarbon gas and inert gas, the first and second electrodes being connected to an RF power supply of an atmospheric pressure plasma generator; and approaching the workpiece to the first electrode downstream of a reaction gas flow passing through the discharge space, such that the plasma created in the discharge space is transferred into a space between the first electrode and the workpiece to generate a second atmospheric pressure glow plasma therein, whereby a fluorocarbon coating layer can be formed on the surface of the workpiece.

Claims

1. A method of coating a surface of a workpiece with fluorocarbon, comprising the steps of:

generating first atmospheric pressure glow plasma by supplying a reaction gas into a discharge space formed between a first electrode and a second electrode, the reaction gas containing hydrogen gas, fluorocarbon gas and inert gas, the first and second electrodes being connected to an RF power supply of an atmospheric pressure plasma generator; and

approaching the workpiece to the first electrode downstream of a reaction gas flow passing through the discharge space, such that the plasma created in the discharge space is transferred into a space between the first electrode and the workpiece to generate a second atmospheric pressure glow plasma therein, whereby a fluorocarbon coating layer can be formed on the surface of the workpiece.

2. The method as claimed in claim 1, wherein the fluorocarbon gas is selected from the group consisting of CF₃, CF₄, C₂F₆, C₄F₈ and a mixture thereof.

3. The method as claimed in claim 1, wherein a volume ratio of the fluorocarbon gas and hydrogen gas contained in the reaction gas (fluorocarbon/hydrogen) is within a range of 0.1 to 10.

4. The method as claimed in claim 3, wherein a volume of the inert gas contained in the reaction gas is at least 90% of a total volume of the reaction gas.

5. The method as claimed in claim 4, wherein the inert gas includes helium gas, and a volume of the helium gas is at least 60% of a total volume of the inert gas.

6. The method as claimed in claim 1, wherein an RF power supply operating at a frequency of 100 KHz to 60 MHz is employed to generate the plasma.

7. The method as claimed in claim 6, wherein the workpiece approaches the first electrode within a range of 1 to 10 mm.

8. The method as clamed in claim 5, wherein an RF power supply operating at a frequency of 100 KHz to 60 MHz is employed to generate the plasma and the workpiece approaches the first electrode within a range of 1 to 10 mm.

9. The method as claimed in claim 1, wherein:

the first electrode of the plasma generator takes the shape of a rod with a predetermined length;

the second electrode is spaced apart from the first electrode by a predetermined distance along a longitudinal direction of the first electrode to thereby form a discharge space between the electrodes;

the plasma generator further includes a gas supply unit formed with a passage through which the reaction gas can be supplied to the discharge space; and

the passage includes a buffer space formed along a longitudinal direction of the first electrode, a mixing space formed along the longitudinal direction of the first electrode and having one side opened toward the discharge space, and an orifice for allowing the buffer space and an inner wall of the mixing space to communicate with each other.

10. The method as claimed in claim 1, wherein:

the first electrode of the plasma generator takes the shape of a rod with a predetermined length;

the second electrode is spaced apart from the first electrode by a predetermined distance along a longitudinal direction of the first electrode to thereby form a discharge space between the electrodes; and

the plasma generator further includes a gas supply unit formed with a passage through which the reaction gas can be supplied to the discharge space, and a capacitor connected to the first electrode.

11. The method as claimed in claim 9, wherein the plasma generator further includes a capacitor connected to the first electrode.

17. The method as claimed in claim 4, wherein the inert gas includes helium gas, and a volume of the helium gas is at least 60% of a total volume of the inert gas.

20. The method as clamed in claim 17, wherein an RF power supply operating at a frequency of 100 KHz to 60 MHz is employed to generate the plasma and the workpiece approaches the first electrode within a range of 1 to 10 mm.

12. A method of coating a surface of a workpiece with fluorocarbon, comprising the steps of:

generating first atmospheric pressure glow plasma by supplying a reaction gas into a discharge space formed between a first electrode and a second electrode, the reaction gas containing hydrocarbon gas, fluorocarbon gas and inert gas, the first and second electrodes being connected to an RF power supply of an atmospheric pressure plasma generator; and

approaching the workpiece to the first electrode downstream of a reaction gas flow passing through the discharge space, such that the plasma created in the discharge space is transferred into a space between the first electrode and the workpiece to generate a second atmospheric pressure glow plasma therein, whereby a fluorocarbon coating layer can be formed on the surface of the workpiece.

13. The method as claimed in claim 12, wherein the hydrocarbon gas is selected from the group consisting of C₂H₂, CH₄, C₂H₄, C₂H₆, C₃H₈ and a mixture thereof.

14. The method as claimed in claim 13, wherein the fluorocarbon gas is selected from the group consisting of CF₃, CF₄, C₂F₆, C₄F₈ and a mixture thereof.

15. The method as claimed in claim 12, wherein a volume ratio of the fluorocarbon gas and hydrocarbon gas contained in the reaction gas (fluorocarbon/hydrocarbon) is within a range of 0.1 to 10.

16. The method as claimed in claim 15, wherein a volume of the inert gas contained in the reaction gas is at least 90% of a total volume of the reaction gas.

18. The method as claimed in claim 12, wherein an RF power supply operating at a frequency of 100 KHz to 60 MHz is employed to generate the plasma.

19. The method as claimed in claim 18, wherein the workpiece approaches the first electrode within a range of 1 to 10 mm.

21. A method of coating a surface of a workpiece with fluorocarbon, comprising the steps of:

generating an atmospheric pressure glow plasma by supplying an atmospheric pressure plasma generator with a reaction gas containing hydrogen gas, fluorocarbon gas and inert gas; and

exposing the workpiece surface to the generated atmospheric pressure glow plasma to thereby form a fluorocarbon coating layer on the workpiece surface.

22. The method as claimed in claim 21, wherein the fluorocarbon gas is selected from the group consisting of CF₃, CF₄, C₂F₆, C₄F₈ and a mixture thereof.

23. The method as claimed in claim 21, wherein a volume ratio of the fluorocarbon gas and hydrogen gas contained in the reaction gas (fluorocarbon/hydrogen) is within a range of 0.1 to 10.

24. The method as claimed in claim 23, wherein a volume of the inert gas contained in the reaction gas is at least 90% of a total volume of the reaction gas.

25. The method as claimed in claim 24, wherein the inert gas includes helium gas, and a volume of the helium gas is at least 60% of a total volume of the inert gas.

26. The method as claimed in claim 21, wherein in the glow plasma generating step, the atmospheric pressure plasma generator uses an RF power supply operating at a frequency of 100 KHz to 60 MHz.

27. A method of coating a surface of a workpiece with fluorocarbon, comprising the steps of:

generating an atmospheric pressure glow plasma by supplying an atmospheric pressure plasma generator with a reaction gas containing hydrocarbon gas, fluorocarbon gas and inert gas; and

exposing the workpiece surface to the generated atmospheric pressure glow plasma to thereby form a fluorocarbon coating layer on the workpiece surface.

28. The method as claimed in claim 27, wherein the fluorocarbon gas is selected from the group consisting of CF₃, CF₄, C₂F₆, C₄F₈ and a mixture thereof.

29. The method as claimed in claim 28, wherein the hydrocarbon gas is selected from the group consisting of C₂H₂, CH₄, C₂H₄, C₂H₆, C₃H₈ and a mixture thereof.

30. The method as claimed in claim 27, wherein a volume ratio of the fluorocarbon gas and hydrocarbon gas contained in the reaction gas (fluorocarbon/hydrocarbon) is within a range of 0.1 to 10.

31. The method as claimed in claim 30, wherein a volume of the inert gas contained in the reaction gas is at least 90% of a total volume of the reaction gas.

32. The method as claimed in claim 31, wherein the inert gas includes helium gas, and a volume of the helium gas is at least 60% of a total volume of the inert gas.

33. The method as claimed in claim 27, wherein an RF power supply operating at a frequency of 100 KHz to 60 MHz is employed to generate the plasma.

34. A method of coating a surface of a workpiece with hydrocarbon, comprising the steps of:

generating first atmospheric pressure glow plasma by supplying a reaction gas into a discharge space formed between a first electrode and a second electrode, the reaction gas containing hydrocarbon gas and inert gas, the first and second electrodes being connected to an RF power supply of an atmospheric pressure plasma generator; and

approaching the workpiece to the first electrode downstream of a reaction gas flow passing through the discharge space, such that the plasma created in the discharge space is transferred into a space between the first electrode and the workpiece to generate a second atmospheric pressure glow plasma therein, whereby a hydrocarbon coating layer can be formed on the surface of the workpiece.

35. The method as claimed in claim 34, wherein the hydrocarbon gas is selected from the group consisting of C₂H₂, CH₄, C₂H₄, C₂H₆, C₃H₈ and a mixture thereof.

36. The method as claimed in claim 35, wherein a volume of the inert gas is at least 90% of a total volume of the reaction gas.

37. The method as claimed in claim 36, wherein a volume of gas selected from the group consisting of helium, argon and the mixture thereof is at least 60% of a total volume of the inert gas.

38. The method as claimed in claim 34, wherein:

the first electrode of the plasma generator takes the shape of a rod with a predetermined length;

the second electrode is spaced apart from the first electrode by a predetermined distance along a longitudinal direction of the first electrode to thereby form a discharge space between the electrodes;

the plasma generator further includes a gas supply unit formed with a passage through which the reaction gas can be supplied to the discharge space; and

the passage includes a buffer space formed along a longitudinal direction of the first electrode, a mixing space formed along the longitudinal direction of the first electrode and having one side opened toward the discharge space, and an orifice for allowing the buffer space and an inner wall of the mixing space to communicate with each other.

39. The method as claimed in claim 34, wherein:

the first electrode of the plasma generator takes the shape of a rod with a predetermined length;

the second electrode is spaced apart from the first electrode by a predetermined distance along a longitudinal direction of the first electrode to thereby form a discharge space between the electrodes; and

the plasma generator further includes a gas supply unit formed with a passage through which the reaction gas can be supplied to the discharge space, and a capacitor connected to the first electrode.

40. The method as claimed in claim 38, wherein the plasma generator further includes a capacitor connected to the first electrode.